Getting the right level of performance out of your flight simulator and all add-ons can be a complicated matter, but we will attempt to do our best to inform you of the various options, features and considerations that relate to your overall performance experience.

We highly recommend reading the User’s Guide and the Performance Considerations chapter which cover many of the topics and recommendations covered here.

After years of testing, we have determined a specific priority of performance-related settings:

The complexity of the weather environment

This includes the weather data and number of cloud layers, vertical development, number of drawn cloud sprites, and typically is not under the user’s control other than changing location, historical time period, or maximum number of cloud layers and other synthesis options that can affect the cloudscape complexity

Cloud Draw Distance

The configured cloud draw distance (which can vary dynamically with ASN/AS16 when using minimum and maximum values) drastically affects the number of cloud sprites shown. The minimum acceptable distance should be used to achieve the best performance.

3D Cloud Texture Resolution

When using third-party graphics add-ons that include cloud textures, care should be taken to reduce the texture resolution to a reasonable level to not overload your graphics card. 512x512 resolution is highly recommended in most cases. The lower the resolution, the higher the performance.

Graphics card and related settings

While FSX/P3D do not make optimal usage of GPUs at this time, certain GPU settings including anti-aliasing and transparency anti-aliasing can greatly affect the frame-rate. The minimum acceptable anti-aliasing settings should be used to achieve the best performance.

ASN/AS16 Performance-related Settings

As mentioned in #2, cloud draw distance has a significant effect on performance and memory. Values larger than 150 should be avoided, because they are associated with increased frequency of Out of Memory (OOM) cases and/or other abnormalities, such getting no clouds rendered.

Most METARs contain a maximum of 2 to 3 cloud definitions. So, in most cases the Maximum Cloud Layer option should be set accordingly. Note, that this setting affects depiction where ASN/AS16 uses interpolation for cloud synthesis.

Using local suppression mode can cause a significant increase in performance, especially during cloud transitions. Enabling local suppression prevents smooth cloud redraws, reducing the number of cloud sprites to ½ in many cases. We highly recommend using this feature if you’ve exhausted other attempts at improving performance.